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Genesis OPC Explorer 2.0

Genesis OPC Server View: Addition, Modification and Removal of Calculated OPC Item(s)



About Genesis OPC Explorer 2.0

Language: Visual C++
Version: 2.0
Size: 5.711 Kb
Installation File: 4606 Kb

The copyrights for Genesis OPC Explorer 2.0 belong to TGMDev. You are allowed to copy and distribute this software provided that it remains unaltered (No software Addition) and free (except a small fee for the software distribution)

Genesis OPC Explorer 2.0 is a freeware but you can contribute to its development by supporting TGMDev.




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Addition, Modification and Removal of Calculated OPC Item(s)

Adding acquired Item(s) to an OPC Group requires beforehand
  1. The selection of an OPC Server (click here to get details on selection of an OPC Server)
  2. The addition of OPC Group(s) (click here to get details on addition of an OPC Group)
  3. The addition of Acquired Item(s) (click here to get details on addition of Acquired OPC Items)

1. Addition of Calculated OPC Item(s)

Trigger Calculated OPC Item(s) Addition

Two methods are available to start the addition of Calculated OPC Item(s)
  • Select the OPC Group to Add Calculated Items(s) to and Click on the Ribbon Button 'Add Calc OPC Item(s)' in the Ribbon Tab 'OPC Server'

  • Add Calculated OPC Item(s) from Ribbon

  • Right-Click the OPC Group (to add calculated item(s) to) in the 'OPC Server Setup' Tree Control and Select the menu 'Add, Modify and Remove Calculated OPC Item(s)'

  • Add Calculated OPC Item(s) from Context Menu

Add Calculated OPC Item(s)

The 'OPC Item Addition, Modification and Removal' dialog box pops up.

Add, Modify and Remove Calculated OPC Item(s)
Add, Modify and Remove Calculated OPC Item(s)


Note that the available acquired OPC items list on the left of the dialog box with Qualified Name and Short Name. The Short Names will be used to make calculation easier.

Suppose you want to compute the normalized flow from the acquired data: Flow (FY_201), Temperature (TY_001) and Pressure (PY_201).
using the formula: Flow Normalized = Measured Flow × (Temperature K Normal / Measured Temperature K) × ( Abs Measured Pressure / Abs Normal Pressure)
where Temperature K is the temperature in Kelvin ( that is Temperature C° + 273.16). Normal Pressure will be 1.033 Bar.

Here are the procedure to add this computation:
Step DescriptionStep Result
Enter the Short Identifier for the New Calculated Data: FY_201_NORM
Select the Acquired Data FY_201 and click on the button 'Insert Acquired Item in Expression'
Continue to Edit the Calculated Expression by typing : * ( 273.16 / (273.16 +
Select the Acquired Data TY_201 and click on the button 'Insert Acquired Item in Expression'
Continue to Edit the Calculated Expression by typing : )) * (( 1.033 +
Select the Acquired Data PY_201 and click on the button 'Insert Acquired Item in Expression'
Finish the Edition of the Calculated Expression by typing : ) / 1.033)
Click on the 'Evaluate button to Check Formula

Click on the 'Add Item' button to Add the Item to the Calculated Item List. The Dialog Box willl then show the new configuration of the OPC group:

Add, Modify and Remove Calculated OPC Item(s)
Add, Modify and Remove Calculated OPC Item(s)



Additional features are available to get calculated values:
  1. Use of Built-In Functions

  2. Select one built-in function by cliccking the pull-down button of the Combobox 'Available Functions'

    Add Functions in Calculated OPC Item(s)

    The function will be inserted at the caret position. Move the caret inside the function parenthesis and add an acquired OPC data using the 'Insert Acquired Item in Expression' button. Note that you can also insert calculated data (see next point)

  3. Use of Calculated Data in Calculated Data

  4. Calculated data can be used in other calculated data expression provided that ....it is computed before !!!

    Taking the exemple of computing the normalized flow from the acquired data, this can be done in simpler steps:
    Compute Kelvin Temperature: TY_001_K = TY_001 + 273.16
    Absolute Pressure PY_201_ABS = PY_201 + 1.033
    Normmalized Flow = FY_201 * ( 273.16 / TY_001_K) * ( PY_201_ABS / 1.033)

    Obviously, Indirect calculated items are valid only if intermediary calculated items are already calculated and valid.

 



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Date of Last Modification: 16-08-2017
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